Having discovered a lovely air on a CD with a wonderful backing, I would like to learn to play the piece and then be able to play it against a version of the track without the original whistle. I've tried using Audacity and the technique for removing a vocal to create a "karaoke" track but it doesn't seem to work and remove the whistle. Anyone gone down this road and successfully created their own backing track from an original tune?

Thanks for the tips. I'll give it a try but am realising the problem with this. The particular track I like has a Low F whistle in it so removing it would mean substantially cutting across the backing instruments. But I should find another track that uses a high D whistle and try it with that.

If it's a stereo recording, you can also try phase-inverting one of the channels then mixing both channels down to mono. Works best if the lead is centered and there's good L/R separation of the rest, otherwise much of the rest may also disappear. But yes, I've had good (or at least usable) results with some recordings.